1. Technical Field
Various embodiments of the present invention relate to a magnetic field measurement method of measuring a magnetic field, and the like.
2. Related Art
A device for measuring a weak magnetic field of a magnetic field (biomagnetic field) or the like, such as a magnetic field (magnetocardiogram) from the heart or a magnetic field (magnetoencephalo) from the brain, which is radiated by a living body is known in which an optically-pumped magnetic sensor that irradiates a gas cell having alkali metal atoms sealed therein with linearly polarized light and measures a magnetic field through the rotation of the plane of polarization is used (see, for example, JP-A-2013-108833).
In the measurement of a weak magnetic field using an optically-pumped magnetic sensor, it is necessary to cancel a magnetic field (referred to as an original magnetic field) caused by, for example, an environment of geomagnetism, city noise or the like which is present in a measurement region having a gas cell disposed therein. When the original magnetic field is present, sensitivity to a magnetic field radiated by a measuring object decreases due to the influence thereof, or a decrease in the accuracy of measurement is caused.